Page 220 of the Mueller Report: "Under applicable Supreme Court precedent, the Constitution does not categorically and permanently immunize a President for obstructing justice through the use of his Article II powers . The separation-of-powers doctrine authorizes Congress to protect official proceedings, including those of courts and grand juries, from corrupt, obstructive acts regard less of their source. We also concluded that any inroad on presidential authority that would occur from prohibiting corrupt acts does not undermine the President's ability to fulfill his constitutional mission. The term "corruptly " sets a demanding standard. It requires a concrete showing that a person acted with an intent to obtain an improper advantage for himself or someone else, inconsistent with official duty and the rights ofothers. A preclusion of"corrupt" official action does not diminish the President's ability to exercise Article II powers. For example , the proper supervision of criminal law does not demand freedom for the President to act with a corrupt intention of shielding himself from criminal punishment , avoiding financial liability, or preventing personal embarrassment. To the contrary, a statute that prohibits official action undertaken for such corrupt purposes furthers, rather than hinders, the impartial and evenhanded administration of the law. It also aligns with the President's constitutional duty to faithfully execute the laws. Finally, we concluded that in the rare case in which a criminal investigation of the President ' s conduct is justified, inquiries to determine whether the President acted for a corrupt motive should not impermissibly chill his performance of his constitutionally assigned duties . The conclusion that Congress may apply the obstruction laws to the President ' s corrupt exercise of the powers of office accords with our constitutional system of checks and balances and the principle that no person is above the law."

Mueller reports that because aides and advisers to Trump refused to "carry out orders," the President was prevented from influencing the special counsel's investigation.

Here's the relevant line: "The President's efforts to influence the investigation were mostly unsuccessful, but that is largely because the persons who surrounded the President declined to carry out orders or accede to his requests."